Optimize rotation for in-place
Last updated: February 24, 2026
Quick Overview
Find an efficient solution for rotation given the with follow-up constraint.
Amazon
Coding & Algorithms
Machine Learning Engineer
Amazon
February 24, 2026Machine Learning Engineer
Phone Screen
Coding & Algorithms
Easy
7
4
764 solved
Find an efficient solution for rotation given the with follow-up constraint.
Amazon uses this problem in the Phone Screen to evaluate your algorithmic thinking. They expect you to discuss multiple approaches, analyze trade-offs between them, and implement the optimal solution with clean, readable code.
What the Interviewer Expects
- Identify the correct data structure and algorithm for the problem
- Write clean, bug-free code with proper variable naming
- Analyze time and space complexity correctly
- Handle basic edge cases (empty input, single element)
- Communicate your thought process while coding
Key Topics to Cover
Common algorithm patterns (sliding window, two pointers, BFS/DFS)
Time and space complexity analysis
Data structure selection and trade-offs
Sorting and searching
Hash maps and frequency counting
Edge cases and input validation
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- How would you modify your solution to handle streaming input?
- Can you solve this iteratively instead of recursively (or vice versa)?
- How would you test this solution thoroughly?
Sharpen Your Skills on Codemia
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Practice DSA ProblemsSample Answer
Problem Analysis
The problem of rotating an array in place can be effectively solved using the three reversals algorithm. This approach leverages the observation that to rotate an array of size n by k position...
Approach
- Reverse the entire array: This step transforms the array so that the elements that need to be rotated to the front are at the back in reverse order.
- Example: For `arr = [1, 2, 3, 4, 5, 6, ...
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